Numerical control device

Abstract

The present invention provides a numerical control device capable of improving machining quality in 3D machining. The numerical control device 11 includes a coordinate transformation unit 32 that transforms a position commanded by a machining program into a position on a coordinate system as seen from the workpiece 201, a corner angle calculation unit 33 that calculates the corner angle of a corner 210 formed by connecting three consecutive positions transformed by the coordinate transformation unit 32 with straight lines, and a corner determination unit 34 that determines a corner to be a corner if the corner angle is less than or equal to a preset corner determination angle, and controls the drive axis to decelerate or stop the relative movement between the machining tool and the workpiece based on the determination.

Description

[Technical Field]

[0001] This disclosure relates to a numerical control device for driving and controlling a machining tool that performs three-dimensional machining. [Background technology]

[0002] The machining path may include corner sections. To form a sharp corner shape, it is preferable to decelerate the machining nozzle and adjust the machining conditions at the corner. For example, Patent Document 1 discloses a technology for sharpening the corner shape by automatically detecting corner angles included in the machining path and decelerating the machining nozzle. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2007-203346 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] By the way, there is a type of 3D machining, such as pipe processing, where the workpiece is rotated during machining. In 3D machining, the path of the machining nozzle tip and the actual machining path on the workpiece are different, making it difficult to determine the corners. Therefore, in 3D machining, it is not possible to properly decelerate the machining nozzle and adjust the machining conditions, which makes it difficult to improve machining quality.

[0005] Therefore, the purpose of this disclosure is to provide a numerical control device capable of improving machining quality in three-dimensional machining. [Means for solving the problem]

[0006] The numerical control device of the present disclosure controls the drive shaft of a machining machine having at least one rotating shaft for rotating a workpiece, based on a machining program, and includes: a coordinate transformation unit that transforms a position commanded by the machining program into a position on a coordinate system as seen from the workpiece; a corner angle calculation unit that calculates the corner angle of a corner formed by connecting three consecutive positions transformed by the coordinate transformation unit with straight lines; and a corner determination unit that determines a corner if the corner angle is less than or equal to a preset corner determination angle, and controls the drive shaft to decelerate or stop the relative movement between the machining tool and the workpiece based on the determination.

[0007] The numerical control device of this disclosure provides a numerical control device that can improve the machining quality in three-dimensional machining. [Brief explanation of the drawing]

[0008] [Figure 1] This block diagram outlines the numerical control device of the first embodiment of the present disclosure. [Figure 2A] This is a diagram showing an example of a processing machine and workpiece. [Figure 2B] This figure shows examples of other positional relationships between machining equipment and workpieces. [Figure 2C] This figure shows examples of other positional relationships between machining equipment and workpieces. [Figure 3] This is the formula used in this disclosure. [Figure 4] This diagram shows the command positions used in calculating corner angles. [Figure 5] A block diagram outlines the numerical control device of the second embodiment of the present disclosure. [Figure 6] This table shows the relationship between the cornering angle and the corresponding deceleration setting. [Figure 7] This flowchart shows an example of the procedure for setting deceleration or deceleration stop. [Figure 8] This block diagram shows an overview of a numerical control device according to a third embodiment of the present disclosure. [Figure 9] A table showing the relationship between the corner determination angle, the corresponding return distance, and the machining conditions.

Mode for Carrying Out the Invention

[0009] (First Embodiment) The numerical control device 11 of the first embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 is a block diagram showing an overview of the numerical control device 11 of the first embodiment of the present disclosure. FIG. 2A is a diagram showing an example of a machine tool 101 and a workpiece 201.

[0010] As shown in FIG. 2A, the machine tool 101 controlled by the numerical control device 11 includes at least one or more rotating shafts for rotating the workpiece 201. The X direction, Y direction, and Z direction are shown in FIG. 2A. The X direction, Y direction, and Z direction are directions orthogonal to each other. FIG. 2A shows a rotating shaft parallel to the X direction. The rotating shaft parallel to the X direction is defined as the workpiece rotating shaft RX.

[0011] In the example shown in FIG. 2A, the machining tool included in the machine tool 101 includes a machining head 132. The machining head 132 includes a machining nozzle 134. In the example shown in FIG. 2A, the workpiece 201 is a pipe having a square cross section. The workpiece 201 (pipe) rotates about the workpiece rotating shaft RX.

[0012] The numerical control device 11 drives and controls the machining tool and the workpiece rotating shaft RX based on a machining program. Note that the machining tool and the workpiece 201 shown in FIG. 2A are examples. The machining tool and the workpiece 201 can be variously changed. The machining tool preferably includes at least one of a cutting tool, a laser nozzle, a water jet nozzle, a gas nozzle, and a plasma nozzle.

[0013] The numerical control device 11 will be described with reference to Figure 1. The numerical control device 11 includes a coordinate transformation unit 32, a corner angle calculation unit 33, and a corner determination unit 34. In addition to the coordinate transformation unit 32, the numerical control device 11 further includes a first storage unit 21, a second storage unit 22, a program analysis unit 31, an interpolation processing unit 35, and a drive shaft control unit 40.

[0014] (Coordinate transformation section) The coordinate transformation unit 32 is the part that transforms the position commanded by the machining program into a position on the coordinate system as seen from the workpiece.

[0015] The coordinate system will be explained with reference to Figure 2A. In Figure 2A, arrow A1 indicates the rotation direction of the workpiece 201, and arrow A2 indicates the tilt of the machining head 134. As shown in Figure 2A, there are mainly two types of coordinate systems that can be considered for the machining machine 101. One is the coordinate system as seen from the machine. The coordinate system as seen from the machine is defined as the machine coordinate system C1. The machine coordinate system C1 is a coordinate system that does not rotate with the workpiece 201 even when the workpiece 201 rotates. In the example shown in Figure 2A, the center of the machine coordinate system C1 is located at the workpiece rotation axis RX. Note that this is an example, and the center of the machine coordinate system C1 can be placed at an arbitrary position.

[0016] The other coordinate system is the coordinate system viewed from the workpiece. This coordinate system is defined as the workpiece coordinate system C2. The workpiece coordinate system C2 rotates in conjunction with the rotation of the workpiece 201. In the example shown in Figure 2A, the center of the workpiece coordinate system C2 is located on the workpiece surface 202 of the workpiece 201. Note that this is an example, and the center of the workpiece coordinate system C2 can be placed at any position.

[0017] Figure 2A shows the position commanded by the machining program as the first commanded position P1. The commanded position commanded by the machining program is usually expressed in coordinates of the machine coordinate system C1. Therefore, the coordinate transformation unit 32 transforms the position commanded by the machining program from coordinates of the machine coordinate system C1 to coordinates of the work coordinate system C2. In other words, the coordinate transformation unit 32 transforms the position commanded by the machining program into a position on the work coordinate system C2.

[0018] By converting the position commanded by the machining program to a position on the work coordinate system C2, the corner determination unit 34, which will be explained later, becomes capable of determining the corner. As mentioned above, in 3D machining, where machining is performed while rotating the workpiece 201, the path of the tip of the machining nozzle 134 and the actual machining path on the workpiece 201 are different. In other words, the path understood in the machine coordinate system C1 and the path understood in the work coordinate system C2 are different. Since the path understood in the machine coordinate system C1 is not the path along the machining process, it is not possible to perform correct corner determination based on this path.

[0019] In contrast, the path in the work coordinate system C2 follows the outline of the workpiece 201. The work coordinate system C2 rotates along with the rotation of the workpiece 201. Therefore, the coordinates in the work coordinate system C2 are not affected by the rotation. As a result, when the path is determined in the work coordinate system C2, it becomes possible to determine the corners of the path.

[0020] Therefore, in the numerical control device 11 of this embodiment, the coordinate transformation unit 32 transforms the position commanded by the machining program into a position on the work coordinate system C2. This makes it possible to determine the corner portion even in a machining machine equipped with at least one rotation axis for rotating the workpiece.

[0021] The data flow related to coordinate transformation in the numerical control device 11 will now be explained. The first storage unit 21 stores the machining program. The program analysis unit 31 retrieves the machining program from the first storage unit 21 and analyzes the retrieved machining program. The coordinate transformation unit 32 retrieves at least one of the machining program and the analysis result of the machining program from the program analysis unit 31 and performs coordinate transformation.

[0022] (Corner angle calculation unit) The corner angle calculation unit 33 calculates the corner angle of the corner formed by connecting three consecutive positions transformed by the coordinate transformation unit 32 with straight lines.

[0023] (Corner Judging Section) The corner determination unit 34 determines that the portion (corner) formed by connecting the three transformed positions with a straight line is a corner if the corner angle calculated by the corner angle calculation unit 33 is less than or equal to a pre-set corner determination angle. The corner determination angle used for the determination is stored in the second storage unit 22. The corner determination unit 34 obtains the corner angle from the corner angle calculation unit 33 and the corner determination angle from the second storage unit 22, and then determines whether or not it is a corner.

[0024] Here, the processing in the coordinate transformation unit 32, the corner angle calculation unit 33, and the corner determination unit 34 will be specifically explained with reference to the drawings.

[0025] (Coordinate transformation) First, let's explain the coordinate transformation with reference to Figures 2B and 2C. Figures 2B and 2C, like Figure 2A, show examples of a processing machine 101 and a workpiece 201.

[0026] The rotation angle of workpiece 201 differs between Figure 2B and Figure 2C. Figure 2B shows the state where the orientation of the machine coordinate system C1 coincides with the orientation of the workpiece coordinate system C2. In other words, Figure 2B shows the state where the axis of the machine coordinate system C1 coincides with the axis of the workpiece coordinate system C2. Figure 2C shows the state where workpiece 201 has been rotated by an angle θ1 from the state shown in Figure 2B.

[0027] The procedure for converting a commanded position in the machine coordinate system C1 to a position in the work coordinate system C2 is described below. As shown in Figure 2B, the rotation angle of the work rotation axis RX when the axis of the machine coordinate system C1 coincides with the axis of the work coordinate system C2 is defined as the initial phase θ. i Let's assume that Figure 2B shows the initial phase θ. i This shows the case where is 0. In the example shown in Figure 2B, the cross-section of the workpiece 201 is square, and one coordinate of the workpiece coordinate system C2 is parallel to the workpiece surface 202. Furthermore, one axis of the workpiece coordinate system C2 coincides with one axis of the machine coordinate system C1. Therefore, the initial phase θ i It is set to 0.

[0028] Also, when the axes of the machine coordinate system C1 and the workpiece coordinate system C2 coincide, the distance from the center of the machine coordinate system C1 to the center of the workpiece coordinate system C2 is D = (x w , y w , z w ).

[0029] Next, referring to FIG. 2C, the case where the workpiece 201 is rotated about the workpiece rotation axis RX will be described. FIG. 2C shows a state where the workpiece 201 is rotated by an angle θ1. The commanded position in the state where the workpiece 201 is rotated by the angle θ1 is defined as the second commanded position P2. The coordinates of the second commanded position P2 in the machine coordinate system C1 are (x c , y c , z c ). The coordinates of this second commanded position P2 in the workpiece coordinate system C2 are the coordinates (x, y, z). The coordinates (x, y, z) are the coordinates of the second commanded position P2 as seen from the position rotated by the angle θ1 about the workpiece rotation axis RX. The coordinates (x, y, z) can be calculated by the calculation formula 1 shown in FIG. 3. That is, by the calculation formula 1, the coordinates (x c , y c , z c ) in the machine coordinate system C1 can be converted into the coordinates (x, y, z) in the workpiece coordinate system C2. When the initial phase θ i is not 0, θ1 is the angle obtained by subtracting the initial phase θ i from the rotation angle.

[0030] Note that the calculation formula 1 in FIG. 3 is the calculation formula when the rotation axis of the workpiece 201 is parallel to the X direction. The above calculation can also be applied when the rotation axis is parallel to the Y direction or the Z direction. In FIG. 3, the calculation formula when the workpiece rotation axis is an axis parallel to the Y direction, that is, the rotation axis about the Y axis, is shown as the calculation formula 2. Also, the calculation formula when the workpiece rotation axis is an axis parallel to the Z direction, that is, the rotation axis about the Z axis, is shown as the calculation formula 3.

[0031] (Calculation of corner angle) Next, the calculation of the corner angle will be explained with reference to Figure 4. Figure 4 is a diagram showing the command positions used in the calculation of the corner angle. Three command positions, command position A, command position B, and command position C, are shown in Figure 4. Command positions A, B, and C form a path in this order. The angle (the angle made) of the corner 210 formed when the three coordinate points in the work coordinate system C2, as seen from the workpiece 201, are connected by straight lines, is defined as the corner angle θ2. In the example shown in Figure 4, the corner angle θ2 is the angle made between the line segment connecting command position A and command position B and the line segment connecting command position B and command position C.

[0032] The coordinates of command position A in the work coordinate system C2 are (x A ,y A ,z A ) and the coordinates of command position B in the work coordinate system C2 are (x B ,y B ,z B ) and the coordinates of command position C in the work coordinate system C2 are (x C ,y C ,z C ) In this case, the corner angle θ2 can be calculated using formula 4 shown in Figure 3.

[0033] The corner determination unit 34 determines that the portion formed by connecting the three converted command positions with a straight line, i.e., the corner portion 210, is a corner portion if the corner angle calculated as described above is less than or equal to a preset corner determination angle.

[0034] Based on the determination result by the corner determination unit 34, the drive shaft control unit 40 controls the drive shaft of the machining machine 101 to decelerate or stop the relative movement between the machining tool and the workpiece 201.

[0035] By slowing down or stopping the relative movement of the machining tool and the workpiece 201 at the corner, it becomes easier to make the shape of the corner sharp (formation of a sharp corner).

[0036] As described above, when controlling the drive shaft, an interpolation position may be determined. Then, the drive shaft may be controlled based on the determined interpolation position.

[0037] The numerical control device 11 of this embodiment includes an interpolation processing unit 35. The interpolation processing unit 35 obtains at least one of the machining program and the analysis result of the machining program from the program analysis unit 31 and determines the interpolation position. The interpolation position is an intermediate position in the operation of the drive shaft, for example, a position between command positions. The interpolation processing unit 35 can determine the interpolation position based on the determination result of the corner determination unit 34.

[0038] The drive shaft control unit 40 can control the drive shaft of the machining center 101 according to the determined interpolation position.

[0039] As described above, the numerical control device 11 of this embodiment, by including a coordinate transformation unit 32, a corner angle calculation unit 33, and a corner determination unit 34, makes it possible to improve the machining quality in three-dimensional machining.

[0040] In detail, the numerical control device 11 of this embodiment detects the corner angle from the path of the tool (machining tool, machining head, etc.) as seen from the workpiece 201, or from the path of the tip of the machining nozzle. Based on the detection result, it decelerates or stops the movement of the tool, etc. This makes it possible for the numerical control device 11 of this embodiment to decelerate or stop the tool, etc. at corners in 3D machining. As a result, the amount of inward turning at corners is reduced, and machining quality can be improved.

[0041] (Second embodiment) Referring to Figure 5, a numerical control device 12 of a second embodiment of this disclosure will be described. Figure 5 is a block diagram illustrating the overview of the numerical control device 12 of the second embodiment. The second embodiment will mainly be described in terms of the differences from the first embodiment. Matters not specifically described in the second embodiment can be the same as in the first embodiment.

[0042] The numerical control device 12 of the second embodiment differs from the numerical control device 11 of the first embodiment in the content of the determination made by the corner determination unit 34. In the numerical control device 11 of the first embodiment, the corner determination unit 34 determines that a section is a corner if the corner angle is less than or equal to a preset corner determination angle. In contrast, in the numerical control device 12 of the second embodiment, the corner determination unit 34 determines to decelerate or decelerate and stop based on the deceleration setting corresponding to the smallest corner determination angle that makes the corner angle less than or equal to the corner determination angle, based on the deceleration settings for at least one preset corner determination angle. Thus, the numerical control device 12 of the second embodiment can determine to decelerate or decelerate and stop with a deceleration setting corresponding to the corner angle.

[0043] As shown in Figure 5, in the numerical control device 12 of the second embodiment, the second storage unit 22 stores the deceleration setting in addition to the corner determination angle.

[0044] Figure 6 shows an example of the deceleration settings stored in the second memory unit 22. Figure 6 is a table showing the relationship between each corner judgment angle and the corresponding deceleration setting. As shown in Figure 6, the amount of deceleration increases as the corner judgment angle decreases. The deceleration shown in Figure 6 indicates the target speed for deceleration when reaching the apex of the corner.

[0045] For example, in the example shown in Figure 6, if the corner detection angle exceeds 60° but is 90° or less, the vehicle will decelerate to 15% of the commanded speed. Conversely, if the corner detection angle exceeds 10° but is 30° or less, the vehicle will decelerate to 5% of the commanded speed. Furthermore, if the corner detection angle exceeds 0° but is 10° or less, the vehicle will decelerate and then come to a stop.

[0046] The following describes in detail the determination made by the corner determination unit 34 in the second embodiment. The corner determination unit 34 compares the corner angle calculated by the corner angle calculation unit 33 with a pre-set corner determination angle. During the comparison, the corner determination unit 34 obtains the deceleration setting from the second storage unit 22. It then determines the smallest corner determination angle such that the corner angle ≤ the corner determination angle, and performs deceleration with the deceleration setting corresponding to that corner determination angle.

[0047] Specifically, for example, if the corner angle is 60°, setting No. 3 in Figure 6 will be applied. This means that the deceleration setting will reduce the speed to 10% of the commanded speed.

[0048] Furthermore, if the corner angle is 25°, setting No. 2 in Figure 6 is applied. This results in a deceleration setting of up to 5% of the commanded speed.

[0049] Thus, in the second embodiment, deceleration or deceleration stopping can be performed according to the corner determination angle. As a result, it becomes easier to achieve both improved processing quality and maintenance of productivity.

[0050] In the example shown in Figure 6, the deceleration setting is defined as a ratio of the command speed to the target deceleration speed when reaching the apex of the corner. The method of defining the degree of deceleration in the deceleration setting is not limited to a ratio to the command speed. For example, other methods of definition include the time constant of the acceleration / deceleration filter. For example, when the corner angle is large, the time constant of the acceleration / deceleration filter is set to be large, and when the corner angle is small, the time constant is set to be small. This makes it easier to machine the corner sharply while also maintaining productivity in the machining path. In addition, the target deceleration speed can be set not only as a ratio to the deceleration command, but also, for example, by directly setting the speed value.

[0051] The following describes an example of setting up deceleration or deceleration stop, referring to Figure 7. Figure 7 is a flowchart illustrating an example of the procedure for setting up deceleration or deceleration stop. In the following description and in Figure 7, S1 indicates step 1. The same applies to S2 and subsequent steps.

[0052] (S1) S1 is a coordinate transformation step. In S1, the position commanded by the machining program is transformed into a position in the coordinate system as seen from the workpiece. S1 is performed, for example, by the coordinate transformation unit 32.

[0053] (S2) Step S2 is a corner formation step. In step S2, three consecutive transformed positions are connected by straight lines to form a corner. Step S2 is performed, for example, by the corner angle calculation unit 33.

[0054] (S3) Step S3 is the corner angle calculation step. In S3, the corner angle of the corner is calculated. Step S3 is performed, for example, by the corner angle calculation unit 33.

[0055] (S4) S4 is a corner determination step. In S4, the corner angle is compared with the corner determination angle to determine whether the corner is a corner. S4 is performed, for example, by the corner angle calculation unit 33. If the corner is determined to be a corner (the determination is YES), the step proceeds to S5. If the corner is not determined to be a corner (the determination is NO), the procedure ends without setting deceleration or deceleration stop.

[0056] (S5) Step S5 is a deceleration setting determination step. In S5, based on the deceleration settings for at least one predetermined corner determination angle, it is determined to decelerate or decelerate to a stop using the deceleration setting corresponding to the smallest corner determination angle at which the corner angle becomes less than or equal to the corner determination angle. In other words, the setting for deceleration or decelerate to stop is determined according to the corner angle. Step S5 is performed, for example, by the corner determination unit 34.

[0057] (S6) S6 is a drive shaft control step. In S6, the drive shaft is controlled based on the determined deceleration setting. S6 is performed, for example, by the drive shaft control unit 40. In S6, the procedure for setting deceleration or deceleration stop is completed.

[0058] (Third embodiment) Referring to Figure 8, a numerical control device 13 of a third embodiment of this disclosure will be described. Figure 8 is a block diagram illustrating the overview of the numerical control device 13 of the third embodiment. The third embodiment will mainly be described in terms of its differences from the first embodiment. Matters not specifically described in the third embodiment can be the same as in the first embodiment.

[0059] The numerical control device 13 of the third embodiment includes, in addition to the parts of the numerical control device 11 of the first embodiment, a third storage unit 23, a fourth storage unit 24, a second coordinate transformation unit 36, a movement amount calculation unit 37, a return distance determination unit 38, and a processing condition change unit 41.

[0060] (Second coordinate transformation section) The second coordinate transformation unit 36 ​​is the part that, when the corner determination unit 34 determines that a corner is a corner, transforms the interpolated position of the drive shaft to a position on the coordinate system as seen from the workpiece. The interpolated position generated by the interpolation processing unit 35 is usually shown in coordinates in the machine coordinate system C1. Therefore, the second coordinate transformation unit 36 ​​transforms the coordinates of the interpolated position into coordinates in the workpiece coordinate system C2. The method of coordinate transformation in the second coordinate transformation unit 36 ​​can be the same as the method of coordinate transformation in the coordinate transformation unit 32 described earlier.

[0061] (Movement calculation section) The movement amount calculation unit 37 is the part that calculates the movement amount from the difference between the position transformed by the second coordinate transformation unit of the command block starting point in the machining program and the current position transformed by the second coordinate transformation unit.

[0062] In a machining program, the command block start point is, for example, the command position of a corner 210 that has been determined to be a corner. The command block start point can also be considered the vertex of the corner. In the example shown in Figure 4, command position B is the command block start point. The coordinates of such a command block start point can also be converted to coordinates in the work coordinate system C2 in the same way as the coordinate transformation of the interpolated position.

[0063] The movement amount calculation unit 37 calculates the difference between the starting point of the command block in the work coordinate system C2 and the current position (for example, the interpolated position), and calculates the movement amount of the machining tool from that difference. This makes it possible to accurately determine, for example, the distance from the vertex of a corner to the current position.

[0064] (Recovery distance determination unit) The return distance determination unit 38 is responsible for determining whether the calculated movement amount is within a preset return distance. In the example shown in Figure 8, the third storage unit 23 stores the preset return distance. The return distance determination unit 38 retrieves the preset return distance from the third storage unit 23. Then, the return distance determination unit 38 compares the movement amount with the return distance. In this way, it becomes possible to determine whether the movement is within the return distance based on a finer interpolation position rather than the distance between adjacent command positions. This enables a more appropriate return operation that contributes to improved productivity.

[0065] (Processing condition change section) The machining condition change unit 41 is the part that changes the machining conditions for machining the workpiece when the amount of movement is within the return distance. In the example shown in Figure 8, the fourth storage unit 24 stores the pre-set machining conditions. The machining condition change unit 41 retrieves the pre-set machining conditions from the fourth storage unit 24. Then, the machining condition change unit 41 compares the amount of movement with the return distance.

[0066] In this case, it is preferable that the change in the machining conditions in the machining condition change section 41 is based on the corner angle.

[0067] In the third embodiment, the return distance determination unit 38 can determine whether the return distance is within the set range based on the return distance for at least one predetermined corner determination angle. This is because the return distance, which serves as a reference when changing the machining conditions, is set for each corner determination angle.

[0068] The machining condition changing unit 41 can change the machining conditions based on machining conditions for at least one predetermined corner determination angle. This is because machining conditions are set for each corner determination angle.

[0069] In this way, by pre-setting a reference return distance and machining conditions for each corner judgment angle, it is possible to set machining conditions for the return operation that are suitable for the corner angle of the corner section.

[0070] Furthermore, it is preferable to include at least the feed rate as a machining condition. The feed rate is one of the machining conditions in which the difference in value between the corner and other parts is large. Therefore, by including the feed rate in the machining conditions that the machining condition changing unit 41 changes, a more appropriate return operation becomes possible.

[0071] Furthermore, it is preferable to include at least one of the following as processing conditions: laser output, laser frequency, and laser output duty cycle. When processing is laser processing, the aforementioned laser output, like the feed rate, is one of the processing conditions where the difference in value between the corner and other parts is large. Therefore, by including at least one of the following as processing conditions changed by the processing condition changing unit 41, a more appropriate recovery operation becomes possible.

[0072] Referring to Figure 9, the changes in processing conditions during the return operation will be explained in more detail. Figure 9 is a table showing the relationship between the corner determination angle, the corresponding return distance, and the processing conditions. The table in Figure 9 uses laser processing as an example. The relationship between the corner determination angle and the corresponding return distance exemplified in Figure 9 can be stored in the third storage unit 23. In addition, the relationship between the corner determination angle and the processing conditions exemplified in Figure 9 can be stored in the fourth storage unit.

[0073] First, the corner angle is calculated, and the calculated corner angle is compared with a preset corner determination angle. Then, deceleration or deceleration stopping is performed at the corner using a deceleration setting corresponding to the smallest corner determination angle at which the corner angle becomes less than or equal to the corner determination angle. Up to this point, it is the same as in the first and second embodiments. Next, the return distance and machining conditions are determined based on the smallest corner determination angle at which the corner angle becomes less than or equal to the corner determination angle. At this time, a table that pre-defines the corner determination angle and the corresponding return distance and machining conditions is referred to, as illustrated in Figure 9.

[0074] As shown in Figure 9, the return distance and processing conditions vary depending on the reference corner judgment angle. For example, in setting N.4, where the minimum corner judgment angle is 90°, the return distance is 4.0 mm. The return distance determination unit 38 then determines whether the calculated amount of movement is within the preset return distance of 4.0 mm. If the amount of movement is within 4.0 mm, the processing condition change unit 41 changes the processing conditions based on the preset processing conditions. In the example shown in Figure 9, the feed rate is 1000.0 mm / min, the laser output is 1000.0 W, the laser frequency is 3000.0 Hz, and the laser duty cycle is 80.0%.

[0075] In contrast, in setting N.1, where the minimum corner detection angle is 10°, the return distance becomes longer, the feed rate becomes slower, and the machining conditions become weaker compared to case No. 4 described above. Thus, in the third embodiment, the conditions for the return operation can be set to favorable conditions according to the corner detection angle and further to the deceleration setting at the corner. This makes it easier to optimize the return operation in 3D machining.

[0076] Normally, after decelerating or stopping at a corner, a return operation is performed for a predetermined distance (return distance). During the return operation, machining is performed under machining conditions such as the commanded speed for the return operation and the laser output conditions. In the third embodiment, the return distance is determined from the distance along the path of the tool or machining nozzle tip as seen from the workpiece, and the return operation is performed. In addition, the machining conditions are changed during the return operation. This enables an appropriate return operation.

[0077] The embodiments of the present disclosure have been described above. The present invention is not limited to the embodiments described above, and various modifications, variations, and combinations are possible.

[0078] The following additional information is disclosed regarding the above embodiments and modifications.

[0079] (Note 1) A numerical control device (11) that drives and controls the drive shaft of a machining machine (101) having at least one rotating shaft for rotating a workpiece (201) based on a machining program, A coordinate transformation unit (32) that converts the position commanded by the machining program into a position on the coordinate system as seen from the workpiece, A corner angle calculation unit (33) calculates the corner angle of the corner formed by connecting three consecutive positions transformed by the coordinate transformation unit (32) with straight lines, The system includes a corner determination unit (34) that determines the corner (210) to be a corner when the corner angle is less than or equal to a preset corner determination angle, Based on the determination, the drive shaft is controlled to decelerate or stop the relative movement between the machining tool and the workpiece. Numerical control device (11).

[0080] (Note 2) The corner determination unit (34) determines, based on a predetermined deceleration setting for at least one of the corner determination angles, to decelerate or decelerate to a stop using the deceleration setting corresponding to the smallest corner determination angle that makes the corner angle less than or equal to the corner determination angle. The numerical control device (11) described above.

[0081] (Note 3) The processing tool includes at least one of the following: a cutting tool, a laser nozzle, a water jet nozzle, a gas nozzle, and a plasma nozzle. The numerical control device (11) described above.

[0082] (Note 4) If the corner determination unit (34) determines that it is a corner, a second coordinate transformation unit (36) converts the interpolated position of the drive shaft to a position on the coordinate system as seen from the workpiece, A movement amount calculation unit (37) calculates the movement amount from the difference between the position transformed by the second coordinate transformation unit (36) at the starting point of the command block in the machining program and the current position transformed by the second coordinate transformation unit (36), A return distance determination unit (38) that determines whether the amount of movement is within a preset return distance, The system includes a machining condition changing unit (41) that changes the machining conditions for machining the workpiece (202) if the amount of movement is within the return distance, The processing is carried out based on the modified processing conditions. The numerical control device (11) described above.

[0083] (Note 5) The return distance determination unit (38) determines whether the return distance is within the set return distance based on the return distance for at least one of the set corner determination angles, The processing condition changing unit (41) changes the processing conditions based on the processing conditions for at least one of the pre-set processing conditions for the corner determination angle. The numerical control device (11) described above.

[0084] (Note 6) The aforementioned processing conditions include at least the feed rate, The numerical control device (11) described above.

[0085] (Note 7) The processing conditions include at least one of laser power, laser frequency, and laser power duty cycle. The numerical control device (11) described above. [Explanation of Symbols]

[0086] 11 Numerical control device 12 Numerical control device 13 Numerical control device 21 First Memory Unit 22 Second Memory Unit 23 Third Memory Unit 24. The fourth memory unit 31 Program Analysis Department 32 Coordinate Transformation Unit 33 Corner Angle Calculation Unit 34 Corner Judging Section 35 Interpolation Processing Unit 36 Second Coordinate Transformation Unit 37 Travel amount calculation section 38 Recovery distance determination unit 40 Drive shaft control unit 41 Processing Condition Change Unit 101 Processing machinery 132 Machining head 134 Machining Nozzle 201 Work 202 Work surface 210 corner

Claims

1. A numerical control device that controls the drive shaft of a machining machine having at least one rotating shaft for rotating a workpiece, based on a machining program, A coordinate transformation unit that converts the position commanded by the machining program, which is shown in the machine coordinate system of the machining machine, to a position on the coordinate system as seen from the workpiece, A corner angle calculation unit calculates the corner angle of the corner formed by connecting three consecutive positions transformed by the coordinate transformation unit with straight lines, The system includes a corner determination unit that determines the corner to be a corner portion when the corner angle is less than or equal to a preset corner determination angle, Based on the determination, the drive shaft is controlled to decelerate or stop the relative movement between the machining tool and the workpiece. Numerical control device.

2. The corner determination unit determines, based on at least one predetermined deceleration setting for the corner determination angle, to decelerate or decelerate to a complete stop using the deceleration setting corresponding to the smallest corner determination angle at which the corner angle becomes less than or equal to the corner determination angle. The numerical control device according to claim 1.

3. The processing tool includes at least one of the following: a cutting tool, a laser nozzle, a water jet nozzle, a gas nozzle, and a plasma nozzle. The numerical control device according to claim 1.

4. If the corner determination unit determines that a corner is present, a second coordinate transformation unit converts the interpolated position of the drive shaft, shown in the machine coordinate system of the processing machine, to a position on the coordinate system as seen from the workpiece. A movement amount calculation unit calculates the amount of movement from the difference between the position transformed by the second coordinate transformation unit at the starting point of the command block in the machining program, which is the vertex of the corner portion, and the current position transformed by the second coordinate transformation unit, A return distance determination unit that determines whether the amount of movement is within a preset return distance, The system includes a machining condition changing unit that changes the machining conditions for machining the workpiece if the amount of movement is within the return distance, The processing is carried out based on the modified processing conditions. The numerical control device according to claim 1.

5. The return distance determination unit determines whether the return distance is within the predetermined return distance based on the return distance for at least one of the predetermined corner determination angles, The processing condition changing unit modifies the processing conditions based on processing conditions for at least one of the corner determination angles that have been set in advance. The numerical control device according to claim 4.

6. The aforementioned processing conditions include at least the feed rate, The numerical control device according to claim 4.

7. The numerical control device according to claim 4, wherein the processing conditions include at least one of laser output, laser frequency, and laser output duty cycle.

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